Behavior of large fill dams during earthquake and earthquake damage

This paper describes the behavior of and damage to large fill dams during earthquakes. Although fill dams have been constructed since olden times, there are only records of recent earthquake damage. We analyzed the behavior of fill dams of at least 15 m in height during earthquakes, and investigated the damage to the fill dams. The fact that fill dams that are designed and constructed based on the modern design standards have never been failed but have been only slightly affected by past earthquakes in Japan and other nations suggests that such large fill dams are highly earthquake resistant. The modern conventional design methods (soil engineering control of the bank soil, method for evaluating slip safety, and evaluation method of the foundation ground) are thus fully adequate for determining earthquake resistance.     

汶川地震中江油市水坝震害调查与分析

"5.12"汶川地震,四川省水坝震损严重,典型震害现象包括坝体裂缝、塌陷、滑坡、渗漏、启闭设施损坏和其他附属设施的损毁等.依据绵阳江油市水坝震害科学考察资料,对江油市15座溃坝险情水坝和2座高危险情水坝的震损现象做了初步总结和分析,归纳、总结了震损水坝的特点和经验教训.     

Seismic damage of highway bridges during the 2008 Wenchuan earthquake

Many highway bridges were severely damaged or completely collapsed during the 2008 Wenchuan earthquake.A field investigation was carried out in the strongly affected areas and over 320 bridges were examined. Damage to some representative highway bridges is briefly described and a preliminary analysis of the probable causes of the damage is presented in this paper. The most common damage included shear-flexural failure of the pier columns, expansion joint failure, shear key failure, and girder sliding in the transversal or longitudinal directions due to weak connections between girder and bearings. Lessons learned from this earthquake are described and recommendations related to the design of curved and skewed bridges, design of bearings and devices to prevent girder collapse, and ductility of bridge piers are presented.Suggestions for future seismic design and retrofitting techniques for bridges in moderate to severe earthquake areas are also proposed.     

玛多地震中大野马岭大桥震害机理分析

2021年5月22日青海玛多发生了M_s7.4级地震,从地震中桥梁震害情况看:此次地震的特点是断层北侧震害轻,南侧震害重。位于断层南侧的野马滩大桥是简支梁桥,发生大量落梁,是此次地震中受损最为严重的大桥之一;而位于北侧的大野马岭大桥是连续梁桥,仅发生了部分挡块开裂。其中原因值得深入研究。本文通过有限元分析软件Midas/Civil建立大野马岭大桥（上行线）模型,进行地震反应分析,讨论分析了大野马岭大桥在此次地震中的震害机理。发现南北向的地震动是造成该桥横向挡块破坏的主要原因,东西向地震动因受到桥台和纵向挡块的约束并没有出现严重损伤。若将该桥由连续梁桥变成简支梁桥,地震反应会有所变化,但总体趋势特点变化并不大。另外,本文通过现有资料选定5组地震动作为输入,进行地震反应分析,比较分析不同地震动对该桥的影响,并验证地震动模拟效果。     

"5.12"汶川大地震公路路基震害浅析

通过对汶川地震重灾区高速公路及国省干线公路地震震害调查,介绍了四川绵阳地区公路路基震害基本情况,较为全面地总结了公路路基的震害特点,分析了震害与地层岩性、地质构造的内在关系,提出了路基病害整治的措施与建议.为灾后公路恢复重建工程的规划、勘察设计提供一定的参考.     

汶川地震中都江堰市的房屋震害

对汶川地震中都江堰市1 005栋房屋的现场震害调查资料进行了统计分析。分析表明,经抗震设计的房屋的震害明显低于未经抗震设计的房屋,前者实现了预期的抗震设防目标;在经抗震设计房屋中,钢筋混凝土框架结构房屋的震害相对较轻,底框架砌体结构房屋和砌体结构房屋次之;中高层建筑和低层建筑的震害比多层建筑轻;学校、医院等公用建筑的损坏与住宅建筑相比较重。     

基于已有震害矩阵模拟的群体震害预测方法研究

本文提出了一种群体震害预测方法，根据已有建筑物震害预测结果或震害统计分析结果，按照影响建筑物抗震能力的主要因素，由普查资料统计出的建筑物各影响因素的建筑面积比例得出模拟震害矩阵与已知矩阵的贴近度，最后进行加权平均，建立具体预测对象群体建筑物的震害矩阵。     

考虑结构地震损伤影响的能力谱分析方法

现有能力谱分析方法未考虑结构地震作用下产生的累计损伤影响。本文提出了一种以现；有的能力谱分析方法为基础，通过损伤延性增大系数，引入对结构损伤影响考虑的方法。并通过一幢20层框架结构顶点变形能力的能力谱分析结果与动力弹塑性分析结果的对比，说明了该改进方法的有效性。     

Preliminary investigation of seismic damage to two steel space structures during the 2013 Lushan earthquake

Severe damage to steel space structures is rarely reported when compared to other structural systems damaged during past major earthquakes around the world.Two gymnasiums of steel space structures in downtown Lushan County that were damaged during the 2013 M7.0 Lushan earthquake in China were investigated and the observations are summarized in this paper.Typical damage to these two steel space structures ranges from moderate to severe.Moderate damage includes global buckling and dislocation of bolted connections of truss members,and inelastic elongation of anchor bolts and sliding of pedestal plates of supports.Severe damage includes member fracture caused by local buckling,and fracture failure of anchor bolts and welds.The distribution of structural damage to these two structures is described in detail and future research opportunities are suggested.     

Hydrologic changes associated with the October 28, 1983, Idaho earthquake

Significant hydrologic changes were observed after the magnitude 7.3 earthquake that occurred on October 28, 1983, in central Idaho. Groundwater levels rose by as much as 3 meters near the epicenter. Discharge in many streams and springs increased, in some instances by more than 100%. One warm spring ceased flowing for several days; the flow then resumed and peaked at about nine times its original rate. Available data show no significant changes in water quality following the earthquake.     

汶川地震高烈度区城镇房屋震害简介

汶川8.0级大地震宏观震中地震烈度高达X I度,造成大量房屋结构破坏和倒塌,本文介绍了极震区以及周边高烈度区内部分城镇房屋的典型震害,并给出这些城镇中砖混和底框架多层结构主要破坏等级的比例,同时对某些震害特征和相应的抗震问题进行了简要讨论。     

汶川地震中小学砖混结构教学楼震害特征分析

根据都江堰、彭州、崇州、绵竹四地中小学72幢砖混结构教学楼震害调查资料,按教学楼所在地区峰值加速度分类,分析了砖混结构教学楼的震害特征.震害统计数据表明带壁砖柱是此类结构的抗震薄弱环节.以此为基础,提出了砖混结构教学楼抗震设防的若干建议,可供此类结构教学楼设计和施工参考.     

Lessons in bridge damage learned from the Wenchuan earthquake

A strong earthquake occurred in Wenchuan County, Sichuan Province, China, on May 12, 2008. Shortly after the earthquake, the Turner-Fairbank Highway Research Center of the Federal Highway Administration, in partnership with the Research Institute of Highways, the Ministry of Communication of China, led a reconnaissance team to conduct a post-earthquake bridge performance investigation of the transportation system in the earthquake affected areas. The U.S.transportation system reconnaissance team visited the area during July 20-24, 2008. This paper presents the findings and lessons learned by the team.     

Building pounding damage observed in the 2011 Christchurch earthquake

Building pounding damages observed in the February 2011 Christchurch earthquake are described in this paper. The extent and severity of pounding damage is presented based on a street survey of Christchurch's central business district. Six damage severity levels and two confidence levels are defined to classify the observed damage. Generally, pounding was observed to be a secondary effect. However, over 6% of the total surveyed buildings were observed to have significant or greater pounding damage. Examples of typical and exceptional pounding damage are identified and discussed. Extensive pounding damage was observed in low‐rise unreinforced masonry buildings that were constructed with no building separation. Modern buildings were also endangered by pounding when building separations were infilled with solid architectural flashings. The damage caused by these flashings was readily preventable. The observed pounding damage is compared to that observed in the September 2010 Darfield earthquake to explore if the damage could have been predicted. It is found that pounding prone buildings can be identified with reasonable accuracy by comparing configurations to characteristics previously noted by researchers. However, detailed pounding damage patterns cannot currently be precisely predicted by these methods. Copyright © 2011 John Wiley & Sons, Ltd.     

Earthquake activity during the 1983 Etna eruption

Seismic stations, with automatic P-picking and satellite retransmission were set up on Mount Etna following the eruption started on March 1983. Positions of the stations were chosen in order to complement the permanent telemetered network of Catania University.Comparison between locations obtained by both networks were made for earthquakes recorded by at least 5 ARGOS DCP (Data Collection Platform) stations. We observed a satisfactory agreement for events inside both networks.By merging data of both networks, it has been possible to locate more than 50 earthquakes for which separate computation was not possible due to the low number of arrivals.On 3rd-4th June a swarm of deep seismic events was observed. Hypocenters of these earthquakes are clearly located in a NNW-SSE-trending vertical zone of 5 km width at a depth of 7–36 km.Changes in the distribution of shallow seismic activity, before and after this swarm, have been observed.     

Development of damage probability matrices based on Greek earthquake damage data

A comprehensive study is presented for empirical seismic vulnerability assessment of typical structural types, representative of the building stock of Southern Europe, based on a large set of damage statistics. The observational database was obtained from post-earthquake surveys carried out in the area struck by the September 7, 1999 Athens earthquake. After analysis of the collected observational data, a unified damage database has been created which comprises 180,945 damaged buildings from/after the near-field area of the earthquake. The damaged buildings are classified in specific structural types, according to the materials, seismic codes and construction techniques in Southern Europe. The seismic demand is described in terms of both the regional macroseismic intensity and the ratio αg/ao, where αg is the maximum peak ground acceleration (PGA) of the earthquake event and ao is the unique value PGA that characterizes each municipality shown on the Greek hazard map. The relative and cumulative frequencies of the different damage states for each structural type and each intensity level are computed in terms of damage ratio. Damage probability matrices (DPMs) and vulnerability curves are obtained for specific structural types. A comparison analysis is fulfilled between the produced and the existing vulnerability models.     

Models for reproducing the damage scenario of the Lorca earthquake

A damage scenario modelling is developed and compared with the damage distribution observed after the 2011 Lorca earthquake. The strong ground motion models considered include five modern ground motion prediction equations (GMPEs) amply used worldwide. Capacity and fragility curves from the Risk-UE project are utilized to model building vulnerability and expected damage. Damage estimates resulting from different combinations of GMPE and capacity/fragility curves are compared with the actual damage scenario, establishing the combination that best explains the observed damage distribution. In addition, some recommendations are proposed, including correction factors in fragility curves in order to reproduce in a better way the observed damage in masonry and reinforce concrete buildings. The lessons learned would contribute to improve the simulation of expected damages due to future earthquakes in Lorca or other regions in Spain with similar characteristics regarding attenuation and vulnerability.     

汶川大地震中广元市水库震害调查与分析

汶川8.0级特大地震对四川省广元市的水库造成了不同程度的破坏和重大的经济损失.依据广元市水库地震灾害的现场科学考察资料,对该市53座次高危以上险情的水库进行了震害调查与分析、震前病害统计与分析,可以发现:大多数水库土石坝在震前处于带病运行状态;水库的震害主要包括坝体变形、大坝渗漏、泄水建筑物和附属设施损毁等;地震烈度、震中距、修建年代、土石坝坝型与几何构型,以及水库震前的运行状态是影响水库震害程度的主要因素.该研究丰富了水库土石坝震害的基础性资料,并提出了改进水库土石坝抗震性能设计的建设性意见.     

经验震害矩阵的完善方法研究

近年来我国发生的几次大地震有一些是发生在低烈度区,对地震区已有的建筑物应当怎样来评价它的抗震能力,本文对此进行了探索性的研究。通过将破坏概率离散化得出一次地震中各烈度下震害指数的均值和方差,对比其与标准震害矩阵相应烈度下的值,得到其他烈度下震害指数的均值和方差。我们假设各烈度下震害指数分布都服从Beta分布,由均值和方差反算出Beta分布的未知参数,从而得出其他烈度下各破坏等级的概率值。用本文方法得到的震害矩阵,可为该地区的震害预测和经济损失评估提供科学依据。计算结果表明,本文的方法是可行的。